Source‐height and frequency dependence in sensitivity analysis of near‐ground sound propagation.

2008 ◽  
Vol 124 (4) ◽  
pp. 2550-2550
Author(s):  
Chris Pettit ◽  
D. Keith Wilson
Keyword(s):  
Sensitivity Analysis ◽  
Frequency Dependence ◽  
Sound Propagation

Frequency dependence of sound propagation in superfluid-filled porous media

1994 ◽  
Vol 50 (21) ◽  
pp. 15896-15908 ◽  
Author(s):  
Kevin Warner ◽  
J. R. Beamish
Keyword(s):  
Porous Media ◽  
Frequency Dependence ◽  
Sound Propagation

Impact of Swirl on the Sensitivity of the Radial Mode Analysis in Turbomachinery

2013 ◽  
Author(s):  
Juan D. Laguna ◽  
Michael Bartelt ◽  
Joerg R. Seume
Keyword(s):  
Sensitivity Analysis ◽  
Measurement Errors ◽  
Sound Propagation ◽  
Swirling Flow ◽  
Signal To Noise Ratio ◽  
Sound Field ◽  
Radial Mode ◽  
Mode Analysis ◽  
Mean Flow ◽  
Sound Structure

Sound measurements in turbomachinery are a prerequisite for the study and consequent understanding of sound propagation mechanisms. For analyzing these measurements, the Radial Mode Analysis (RMA) is applied. This method decomposes the transmitted sound field in dominant acoustical modes at specific frequencies. Before an experimental campaign is carried out, measurement parameters are selected such that the uncertainty in the results from the application of the RMA is minimized. In order to minimize uncertainties, a sensitivity analysis of the parameters which influence the overall error of the RMA is performed. This analysis focuses mainly on the output of a measurable quantity, namely on the propagating mode amplitudes. Using a numerical simulation, modal structures are generated based upon real turbine operating data with swirling flow and a characteristic operating temperature. The swirling flow is generated by adding an axial vortex to a constant flow-velocity profile. The results show that the sound field varies under consideration of swirling mean flow compared to uniform flow conditions. In the present case, higher-order modes dominate the propagating sound structure. The parameters studied for assessing the sensitivity are the signal-to-noise ratio of the measurement sensors, the number of triggered revolutions, the azimuthal spacing of the sensors, and a triggering delay. The sensitivity analysis gives a detailed insight into the measurement parameters influencing the output of the RMA, e.g. that small triggering delays cause appreciable measurement errors. This knowledge is used to define the requirements for high fidelity measurements.

scholarly journals Frequency dependence of sound propagation in shallow water: Theory and experiments

1995 ◽  
Vol 98 (5) ◽  
pp. 2897-2897
Author(s):  
Mohsen Badiey ◽  
Kevin P. Bongiovanni ◽  
Indra Jaya ◽  
William L. Siegmann
Keyword(s):  
Frequency Dependence ◽  
Shallow Water ◽  
Sound Propagation ◽  
Shallow Water Theory ◽  
Theory And Experiments
Sign in / Sign up

Export Citation Format

Share Document